1. Field of the Invention
The present invention relates to a thin-film magnetic device, and to an electronic component module having said thin-film magnetic device and a base with wiring.
2. Related Background Art
Electronic devices such as personal computers and mobile telephones have electronic components such as integrated circuits or passive devices such as inductors and capacitors. As electronic devices have become smaller and lighter in recent years, there has been a need for these electronic components to be smaller and shorter in height as well. To meet this need, electronic component have come to be formed using thin-film formation technology. This is led to the use of products (hereinafter referred to as electronic component modules) in which a base having wiring is integrated with a thin-film magnetic device such as a thin-film inductor or a thin-film transistor (see, for example, Japanese Laid-Open Patent Application No. 2004-274004).
An example of a known thin-film magnetic device is one equipped with a solenoid coil wound a plurality of times so as to encircle an upper magnetic film, and a lower magnetic film provided facing the upper magnetic film and with part of the solenoid coil interposed therebetween (see, for example, Japanese Patent No. 3135941). Reduction of leakage of magnetic flux and improvement of inductance are achieved by setting the lower magnetic film.